add a style document schema; break up the common schema into a base and common text elements
make styles indexed by title or descriptive text
style API (WIP) closes #49
fix schema implementation of anyXML
add styles and conditionals to the /api/data index
copy style relaxng to db during make
tests for styles API, closes #50
multiple bugfixes to styles API
Merge branch 'feature/style-api' into develop

Closes #96, closes #50 and closes #49